Astronomy Picture of the Day |
APOD: 2003 August 17 - Natural Saturn On The Cassini Cruise
Explanation:
What could you see approaching Saturn aboard an
interplanetary cruise ship?
Your view would likely resemble
this
subtly shaded image of the gorgeous ringed gas giant.
Processed by the Hubble
Heritage project, the picture intentionally
avoids overemphasizing colour contrasts and presents a
natural looking Saturn
with cloud bands, storms, nearly
edge-on rings, and the small round shadow
of the moon Enceladus near the centre of the planet's disk.
Of course, seats were not available on the only ship currently
en route, the
Cassini
spacecraft.
Cassini flew by
Jupiter at the turn of the millennium and is
scheduled
to arrive at Saturn in the year 2004.
After an extended cruise to a world 1,400 million kilometres
from the Sun, Cassini will tour the
Saturnian
system, conducting a remote, robotic exploration
with software and instruments
designed by
denizens of planet Earth.
APOD: 2006 May 3 - Saturn in Blue and Gold
Explanation:
Why is Saturn partly blue?
The
above picture
of Saturn approximates what a
human
would see if hovering close to the giant ringed world.
The above picture
was taken in mid-March by the robot
Cassini spacecraft now orbiting
Saturn.
Here Saturn's majestic rings appear directly only as a thin vertical line.
The rings show their complex structure in the dark shadows they create on the image left.
Saturn's fountain moon Enceladus,
only about 500 kilometres across, is seen as the bump in the plane of the rings.
The northern hemisphere of
Saturn can appear partly blue for the same reason that
Earth's skies can appear blue -- molecules in the cloudless portions
of both planet's atmospheres are better at scattering blue light than red.
When looking deep into
Saturn's clouds, however, the natural
gold hue of Saturn's clouds becomes dominant.
It is not known why southern Saturn does not show the same blue hue --
one hypothesis holds that clouds are higher there.
It is also
not known why Saturn's
clouds are coloured gold.
APOD: 2004 July 23 - Saturns Rings in Natural Colour
Explanation:
What colours are Saturn's rings?
Recent images
from the Cassini spacecraft now orbiting
Saturn confirm that different rings have slightly different colours.
The above image shows their sometimes-subtle differences in brightness and colour.
The rings
reflect sunlight and so, even if they were perfectly reflecting,
would appear the colour of the Sun.
The ring particles are mostly light water-ice,
although these particles can be shaded by an unknown type of
darker dirt.
Thinner and more isolated rings also naturally appear darker.
The brightest section
pictured above is Saturn's
B ring.
Authors & editors:
Robert Nemiroff
(MTU) &
Jerry Bonnell
(USRA)
NASA Web Site Statements, Warnings, and
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NASA Official: Jay Norris.
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A service of:
EUD at
NASA /
GSFC
& Michigan Tech. U.